How important is A5?

[farrarfan1]

I've been trying to learn as much about Mobil 1 as possible so I've read everything I can find on here about it. One thing I'm concerned about is the new GF-4 SM 5W30 is not rated A5 like the SL GF-3 was, only A1. I have a pretty good idea what the A5 means from what I've found here and at the ACEA site.I've seen a few members that seem to think the SL formula was/is better than the new formula since it isn't A5 certified. Can anyone give an opinion on this? I know there isn't much data yet on how the SM M1 is performing but is an A5 certified oil much better than one that is only A1? As always thanks in advance.

 

[Bryanccfshr]

A5 is a long life economy rating. Meaning it is suggested for longer drains but has an HTHS less than that of an A3 rated oil.
Perhaps Mobil is simply no longer publishing the A5 rating on its "non-Premium" synthetic labels and ratings.

Let me see if this table works..

A2-96 Issue 3 Standard gasoline category. For operation with normal change intervals and loads, requirements unchanged since 1996.

A3-02 Stable viscosity, stay in grade, category with stricter requirements. For high-power engines with long oil change intervals approved by the manufacturer.

A1-02 Energy-saving, catalyzer-friendly category with stricter requirements. Developed especially for low-friction engines, low viscosity, 2.9 mPas < HTHS < 3.5 mPas, engine oil.
Not for use with certain engine types.

A4 -xx Category to be introduced for gasoline direct injection Otto engines with lean-mixture operating capability.

A5-02 Energy-saving, stable viscosity ,stay in grade, category with stricter requirements. Developed especially for high specific power engines operating with low friction, low viscosity, 2.9 mPas < HTHS < 3.5 mPas, engine oil. Suitable for long oil change intervals approved by the manufacturer.
Not for use with certain engine types.

Notice that A5 specifically stays in grade? While A1 does not mention that but is Cat friendly?

Interesting.

 

[drive4show]

Given the last post, it seems like A5 is A3, and more.

So if an oil is A1/A5 -- say, M1 10w30 (both GF-3 and GF-4) -- does it also automatically meet A3?

If that's not how it works, is there an oil that meets A3 and A5? I don't remember seeing one or reading about one that does.

I'm wondering about the folks who say, "I need an A3 oil." Would A5 work for them?

 

[Doug Hillary]

Hi,
A5 is actually A5/B5-04 and if this is mentioned as a requirement for warranty purposes then it is very important that the oil is officially Certified (Code of Practice is in place) as such from ACEA (not just "meets" or is "recommended")

THIS OIL SHOULD NOT BE USED where a A3/B3(or B4)-04 lubricant is specified as there is a likelihood of engine damage in this case

Regards
Doug

[ March 04, 2005, 01:15 AM: Message edited by: Doug Hillary ]

 

[Bryanccfshr]

quote:

---

Originally posted by drive4show:
Given the last post, it seems like A5 is A3, and more.

So if an oil is A1/A5 -- say, M1 10w30 (both GF-3 and GF-4) -- does it also automatically meet A3?

If that's not how it works, is there an oil that meets A3 and A5? I don't remember seeing one or reading about one that does.

I'm wondering about the folks who say, "I need an A3 oil." Would A5 work for them?

---

Nope, A# is a stable viscosity with an HTHS above 3.5 while the A1 and A5 have an HTHS below 3.5.and above 2.9 That is the primary differnce and is based on manufactureres recomendations.

A5 is better for long life because it is supposed to stay in grade. A1 implies to me that it will not stay in grade.

 

[TooSlick]

The new Mobil 1, 5w-30, Extended Performance is still rated ACEA, A5/B5 - I'd simply recommend using that.

The A5/B5 spec is only important if you are running very long drain intervals > 10,000 miles, or using the oil in a turbo application.

TS

 

[Palut]

Is it correct that A3 and A5 are the same, except that A5 requires HT/HS between 2.9 and 3.5, and A3 requires HT/HS greater than 3.5?

 

[Doug Hillary]

Hi,
Palut - they are NOT the same - by a long way!

Regards
Doug